AuPt Alloy Nanoparticles for CO‐Tolerant Hydrogen Activation: Architectural Effects in Au‐Pt Bimetallic Nanocatalysts

Abstract

Colloidal suspensions of AuPt alloy nanoparticles (NPs) were prepared by using a rapid butyllithium reduction of Au3+ and Pt4+ precursors in oleylamine. The resulting 2.5 nm (av) particles were characterized by TEM with EDX, XRD, XPS and UV‐vis spectroscopy. With less butyllithium, nanowires are formed from fused NPs and grow to 100 nm in length. The activities of three different AuPt NP architectures (alloy, contact aggregate and monometallic NPs) were evaluated for catalytic hydrogen oxidation in CO‐contaminated fuel streams (1.0 % Pt loadings in Al2O3 supports). The alloy catalyst showed superior H2 and CO oxidation activity, was unaffected by iron promoters and appears to operate by a different mechanism. The heteroaggregate showed a marked improvement in activity with iron promoters and is more selective for CO oxidation.

Synthesis of Cu3Sn Alloy Nanocrystals through Sequential Reduction Induced by Gradual Increase of the Reaction Temperature

“…Then, the reaction solution (OAC, ODE) was heated to 260 8C for 10 min and 6 mL of oleylamine (OAm) was added by syringe. When the reaction temperature had again stabilized at 260 8C, the precursor solution of Cu(acac) 2 and Sn(acac) 2 was injected to the reaction flask. The temperature was elevated to 310 8C at a heating rate of 2 8C min À1 , and kept at this temperature for 1 h. During heating the light yellow solution turned to reddish brown, which indicates the nucleation of Cu and Sn.…”

“…[1,2] Over the past several years, many researchers have focused on the development of methods for the synthesis and mechanism analysis of bimetallic or ternary alloys of transition metals with various nanostructures such as core-shell, [3] hetero, [4] and mixed structures.…”

“…At the initial step, as soon as the precursor solution, the mixture of Cu(acac) 2 , Sn(acac) 2 , OAM, and benzyl ether, is injected into the preheated reactor (260 8C), amine complexes of Cu II and Sn II are formed. [21,22] At this step, Cu(acac) 2 begins to be reduced to metallic copper, whereas the Sn(acac) 2 amine complex remains unchanged.…”

“…Also, we investigated the formation mechanism of Cu 3 Sn nanocrystals by TEM, EDS and UV/Vis spectroscopy, and XRD. In the synthesis, Cu(acac) 2 and Sn(acac) 2 were used as precursors, and oleylamine acts as mild reducing agent. Oleic acid and oleylamine also served as capping agents.…”

Preparation of Nanoporous Pd by Dealloying Al-Pd Slice and Its Electrocatalysts for Formic Acid Oxidation

“…21 The price of palladium is only about half that of platinum and its poison resistance against CO is stronger, so it could be regarded as a proper alternative. Furthermore, the catalytic activity of np-Pd towards formic acid oxidation (FAO) 22 in the alkaline medium is much stronger than that of nanoporous Pt. 23,24 The precursors usually used in many researchers' work [25][26][27][28] which could greatly reduce the corrosion time to obtain nanoporous metals were usually ultrathin ribbons of about 20-50 lm in thickness.…”